Balloon.



M. VANIMAN.

BALLOON. APPLIUATION FILED JAN.29, 1912. RENEWED NOV. 7, 1013.

1,081,?M. Patented Dec. 16, 1913.

E y. E

MELVIN VANIMAN, 0F ATLANTIC CITY, NEW JERSEY, ASSIGNOR T0 INTERNATIONAL AERONAUTICAL CONSTRUCTION COMPANY, A CORPORATION OF MAINE.

BALLOON.

Specification of Letters Patent.

Application fiIed'January 29, 1912, Serial No. 674,008. Renewed November 7, 1913. Serial No. 799,916.

To all whom it may concern:

Be it known that I, MELVIN VANIMAN, a citizen of the United States, and a resident of Atlantic City, in the county of Atlantic and State of New Jersey, have invented a new and useful Improvement in Balloons, of which the following is a specification.

In balloons, as now constructed, the great difficulty lies in the lack of strength of the material to withstand the considerable pressures which are caused by a rise in temperature of the contained gas and which excess pressure tends to tear the balloon fabric. Balloons, more especially the dirigible variety, are necessarily made quite large and, being of a general cylindrical shape, their d1- ameter may readily reach 50 feet. If we assume a rise in temperature of the contained gas of 50 F. this will represent an increase in pressure of 1.5 pounds to the square inch. But on a balloon 25 feet in diameter, calculation shows this to represent a circumferential strain tending to rupture the balloon of 250 pounds along one inch of the fabric, longitudinally or axially measured. If the balloon is 50 feet in diameter then the circumferential strain tendin to rupture a longitudinal inch of fabric is nearly 500 pounds. Such strains are beyond the capacity of known fabrics to withstand. It fol ows, since a balloonist, in. the course of a days journey, may meet with variations in temperature as great as 50 F., that he is compelled to permit the contained gas to escape during those periods in which the balloon is growing warmer in order that the structure may not burst. This has as a result that he must discharge ballast when the balloon again grows cooler for his balloon now contains less gas and has, therefore, less lifting capacity. But any discharge of ballast means the shortening of the ultimate length of the journey which the balloonist may hope to take.

The difficulties to which I have 'ust referred have been to some extent 0 viated, not by attempting to increase the strength of the fabric, but by the use of expansible and collapsible air compartments inside the balloon containing air instead of gas. \Vhen the temperature rises and the gas expands, air is permitted to escape and the collapsible air compartment contracts, thus keeping the volume of the balloon the same with no increase of pressure. When the temperature falls and the gas contracts, air is pumped into the air compartment, the volume of the balloon and the pressure on its fabric not being changed by this operation. The use of such compartments, however, naturally decreases the carrying ca acity of the balloon and is, therefore, to e reduced to the lowest possible limit.

In my inventionI build a balloon of the ordinary two ply silk or cotton fabric and inflate the same so that it takes its final cylindrical shape for it is to be understood that my invention is peculiarly adapted for the elongated type of balloon. I thereupon take a fabric the warp of which is composed nal steel wires alongside of which may also run parallel longitudinal threads of silk, cotton or other fibrous material, and the weft of which is composed of threads of similar fiber. Such fabric I may water proof and make a poor conductor of heat by impregnating its interstices with rubber and ashestos fiber, or the like. This fabric may be woven in long lengths. I now cover the balloon with a. series of len ths of this fabric, each length as long as the balloon and the several lengths juxtaposed by being laid side by side, so that, when taken together they go completely around the balloon. I thus get strength as against axial pressures tending to rupture the balloon. I thereupon wind around the cylindrical balloon, which is now covered with a set of displaced steel wired parallel to its axis, a helical windin of the same fabric. I thus cover the ba loon with a second layer of juxtaposed strips of fabric containing a set of parallel helices of steel wire tending to prevent rupture against circumferential pressures. Moreover, as the axial pressure of the contained gas and consequent tension on the balloon fabric is but half the circumferential pressure of the contained gas and consequent tension on the balloon fabric, I may use either half as many wires or the same number of wires with half the cross-sectional area in my longitudinal as in my circumferential wrapping. This enables me to save one-third of the total weight of the wire actually applied.

I find by using 16 steel or piano wires,

side by side, in one inch crosswise of the .of the strength giving strands of longitudifabric and by taking the diameter of this wire at about .3 mm. for the circumferential or helical wrapping and employing'a wire of half the cross-sectional area for the longitudinal wrapping, that with a balloon 50 feet in diameter and of appropriate length, say 500 feet, I can make it strong enough to withstand the increase in pressure caused by an increase in temperature of the contained gas of 50 F., without using up more than about 10% of the total lifting capacity of the structure. i

In the drawings Figure 1 shows the general shapeof the balloon which I employ. Fig. 2 shows the same with the axial layers of fabric applied thereto, the illustration belng diagrammatic and not to scale. Fig. 3 shows the balloon with a helical wrapping of fabric. Fig. 4 shows a cross-section of the fabric. Fig. 5 shows a cross'section of the balloon cloth with the axial and circumferential wrappings applied thereto, and

Fig. 6 shows a detail.

I make my fabric F by taking a number of strength giving strands of steel wires A and preferably a number of parallel threads A which I use as the warp and connect these by a weft of non-strength giving threads B in the usual manner. stices T fill with acoating of rubber and fibers of asbestos, the one to act as a waterproofing .material the other as a non-conductor of heat.

The elongated balloon, which is built of j the usual two or three ply balloon fabric D, having been inflated until it assumes the cylindrical or sausage shape of Fig. 1, I now apply the appropriate number of longitudinal strips of my fabric thereto, each strip being parallel to the axis, the lateral edges of the separate strips being abutted or juxtaposed and the length of the strip being a trifle greater than the total length of the balloon in order to make up for the cone shape at each end. Since, in this layer, the strength of the cross threads is not relied on, it follows that it isunnecessary to connect the abutting edges of the fabric crosswise, at least in any strength giving fashion. I also taper the ends of the strips, as shown in Fig. 2, so that they may lie on the cones just mentioned. If necessary I may overlap these tapered ends, as shown in Fig. 6, to produce greater strength and to prevent the longitudinal wires from pulling out at their ends. The prcssures and consequent tensions at the conical ends of the balloon, however, decrease with a decrease of the crosssectional diameter and the wires in the fabric are firmly bound therein by the cementing rubber which constitutes a part thereof, so that the danger of having these longitudinal wires pull out at the ends is obviated.

The balloon having been covered with a.

The intermemes set of longitudinal wires parallel with each other and with the axis of the structure, I now wind thereon the wires which are to resist circumferential strain by wrapping my fabric around the balloon in a helical form, as roughly indicated in Fig. 3. This covers the structure with a set of juxtaposed strips or windings of fabric containing a set of parallel helices of circumferential wires, each set containing as many wires as are found in a width of the fabric. Again there is no need of connecting, at least in any strong fashion, the abutting edges of adjacent strips of fabric. It is clear, as before explained, that it will be desirable to make these circumferential wires proportionately more numerous or stronger, in fact something like twice as numerous or twice as strong as those axially applied. This means that the weight of a unit of surface will be twice as great in one case as in the other.

It is obvious that an advantage lies in wrapping the circumferential layer in helical form for if we were to cover the balloon with a set of circular wrappings in a plane strictly at right angles to its axis, this would necessitatecutting the fabric into a number of pieces equal in length to the circumference of the cylinder and making a'joint in each piece.

It is also clear that no considerable care need be taken in applying the circumferential wrapping to the conical ends since the pressure and consequent tension here grows less as we approach the apex of the cone and the need for the strength imparted by my fabric diminishes.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. A. balloon having a layer of strips of fabric with strength giving strands running longitudinally of the fabric; and a second layer of strips of similar fabric having the strips, and consequently the strength giving strands, arranged at an angle to those of the first layer, substantially as described.

2. An elongated balloon having alayer of strips of fabric woven of wire and thread having its wire strength giving strands running longitudinally of the fabric; and a second layer of strips of similar fabric having the strips, and consequently the strength giving strands, arranged at an angle to those of the first layer, substantially as described.

3. An elongated balloon'having a layer of strips of fabric containing parallel wires all running longitudinally and a second layer of strips of similar fabric having the strips and wires arranged at an angle to those of the first layer substantially as described.

4. An elongated balloon covered with a layer containing an axial set of juxtaposed Mil strips of fabric having a warp of wire and a tionetely greater weight per unit of balloon 10 Weft of thread and a second layer containarea, substantially as described.

ing a helical wrapping of juxtaposed strips In testimony whereof, I have signed my or windings of a similar fabric, substanname to this specification, in the presence of tially as described. two subscribing Witnesses.

5. An elongated balloon covered with a MELVIN VANIMAN. set of parallel Wires in the direction of the Witnesses: axis, and a second set of parallel wires cir- LOUELLA F. L'rrrnn,

euinferentially arranged having a propor- D. HAROLD BUSH. 

